Sustainable three-dimensional hydrophobic and oleophilic robust biomass-based foam for efficient solar-assisted oil-water separation

Marine pollution resulting from offshore oil spills poses significant threats to marine ecosystems, biodiversity, and human health. Consequently, developing efficient and eco-friendly oil-absorbent materials has emerged as critical for addressing this pressing environmental challenge. In this work, we successfully synthesized a novel three-dimensional porous foam with dual hydrophobicity and oleophilicity, fabricated through the integration of esterified orange peel (OP-E), polylactic acid (PLA), and carbon dots (CDs) for solar-assisted oil-water separation. Notably, the OP-E/PLA/CDs foam demonstrated exceptional absorption capacities, reaching 21–27 times its own weight for various low-viscosity oils. This enhanced performance stems from the esterification process, which substantially modifies the crystalline structure of cellulose to form an interconnected 3D network optimized for oil absorption. The incorporation of carbon dots substantially improved the composite's performance, boosting both solar-to-thermal conversion efficiency and thermal conductivity. Importantly, the esterification process introduced carbon-carbon double bonds from acrylamide molecules (rich in amide groups) into the cellulose matrix, yielding a foam with superior mechanical properties. The material maintained an impressive 95.6 % shape recovery ratio even under stress up to 500 g. Leveraging these advantageous properties, we developed an energy-free oil collection system capable of absorbing approximately 19.6 g of crude oil within 60 min. This work not only presents a scalable and cost-effective strategy for fabricating high-performance oil-absorbent materials but also establishes a practical zero-energy solution for offshore oil spill remediation.